1. Field of the Invention
The present invention relates to the field of computer networks that support the transmission of electronic mail (e-mail) and more particularly to the controlled expiration of e-mail single store attachments.
2. Description of the Related Art
In today's business world, e-mail is the most widely used business communication tool to exchange critical business information. The usage of corporate e-mail has been growing rapidly at a rate of 30% per year, or even faster according to recent industry statistics.
E-mail also has become a day-to-day tool for workgroup collaboration. E-mail messages and attachments are very often copied and forwarded many times within the workgroup only to make overall e-mail storage grow even faster. Furthermore, for regulatory and business continuity reasons, many corporations are clustering their mail servers and implementing e-mail content journaling to protect this critical information asset.
As a result, the overall volume of e-mail, measured in storage requirements, has increased as much as tenfold. This rapid increase of e-mail database size and traffic volume has caused many organizations to deal with e-mail overload issues such as additional physical storage requirements, mail server performance degradation, and extra administrative burdens e.g., longer backup time. When organizations maintain e-mail databases at an optimum size for mail server performance, organizations must reduce the number of users per server as the average e-mail storage space per user increases. Oftentimes additional mail servers, bandwidth and storage capacities are deployed or ad-hoc mail quotas are imposed to e-mail users to ease these concerns.
Industry experts attribute much of the e-mail overload to e-mail attachments. Several recent studies report that attachments account for more than 85% of all e-mail data. E-mail attachments consume a major portion of corporate e-mail resources, e.g., as much as 90%, to transmit, process and administer as e-mail storage.
One proposed method to reduce the proliferation of e-mail attachments is the use of a single instance storage repository for e-mail attachments. In general, an e-mail processor task module processes through mail files and replaces e-mail attachments with a link, e.g., an attachment link, based on a set of predefined rules, and stores a single copy of the attachment in a single instance storage repository. Thereafter, the intended one or more recipients will receive the e-mail message with an attachment link but not the attachment itself. Although initial e-mail storage savings are realized using the replacement attachment links, two significant problems remain.
First, the storage savings are temporary, in that when a message forward or reply is performed in the above-described process, the actual attachment is restored to the e-mail message and transmitted to the one or more intended recipients instead of the existing attachment link. When this forward or reply is subject to additional forward or reply, multiple copies of the attachment will flood the e-mail system potentially placing the e-mail system in even a worst mail storage space crisis. Second, the above-described process fails to address file management concerns of the newly created single instance message storage repository. More specifically, as more and more attachments are stored on the single instance message storage repository, file management rules are necessary to prevent additional mail storage space crises.